Recently, power supply devices employing a Switch-Mode Power Supply (SMPS) are being focused, and the SMPS uses a switching device such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or a Bipolar Junction Transistor (BJT), or a transformer to stably provide a power source.
Meanwhile, concomitant with a trend toward development of miniaturization, reduced slim, light weight size of home electronic appliances, the SMPS is required to slim, and researches are continuously made to reduce volume or size of a transformer that takes the lion's share of a circuit component comprising the SMPS.